Process for the liquid phase sulphation of normal butene



Patented Sept. 27, 1932 UNITED STATES PATENT I OFFICE BENJAMIN T. BROOKS, OF GREENWICH, CONNECTICUT, ASSIGNOB TO PETROLEUM CHEMICAL CORPORATION, A CORPORATION OF DELAWARE PROCESS FOR THE LIQUID PHASE SULPHATION OF NORMAL BUTENE No Drawing.

The butene for this purpose may be generated by the destructive distillation of materials generally containing carbon and hydrogen. One preferred method of generating the same consists in cracking petroleum or shale oil, and such oils will be hereinafter referred to generically by the term mineral oils. When cracking mineral oils to produce gasoline, a mixture of hyrocarbons is obtained ranging from the charge stock, through kerosene and gasoline to the normally gaseous hydrocarbons, up to and includmg methane. After condensation and removal of the normally liquid hydrocarbons, there remains a residue of normally aseous hydrocarbons which contains ole nes predominantly of not exceeding 4 carbon atoms to the molecule and may include a minor proportion of olefines of 5 carbon atoms to the molecule. One commercial method for the sulphation of the normal butene contained in such mixture consists in separating therefrom a fraction the olefine content of which consists predominantly of olefines of 4 carbon atoms to the molecule, and sulphating such fraction in liquid phase by contacting the same with aqueous sulphuric acid. In general, acid of from 70 to"80%, H 80 content, has been employed for this purpose at LIL) temperatures ranging from to C. The temperature has been limited to prevent excessive polymerization, and for this purpose it has been necessary to resort to refrigeration of the reacting materials. This has constituted an additional expense to the process.

I have now found that I may successfully carry out this reaction at higher temperatures by the use of a range of lower acid concentration and with excellent reaction efiiciencies. I am thereby enabled to effect substantial economies in the process by eliminating entirely the refrigeration heretofore employed, and simultaneously effect economies in the reconcentration of the acid. It is a further novel result of the new ratio of temperatures and acid concentrations that even when reacting with the theoretical quantity of sulphuric acid for the formation of the mono-alkyl sulphate I am enabled to form substantial quantities of dialkyl sulphate,

Application filed September 16, 1930. Serial No. 482,874.

and by reducing the acid ratio I am enabled to increase the relative amount of dialkyl sulphate formed nd to attain this condition more rapidly t an would otherwise be possible.

In general, I effect the sulphation of the butene by the employment of aqueous sulphuric acid containing from to H SO content, at temperatures ranging from 30-to 55 C., and my preferred conditions comprise the employment of an acid of from 65 to 68%, H SO content, both limits inclusive, at temperatures ranging from 35 to 45 C.

Where the fraction containing the butene is generated by cracking mineral oil, other olefines, such as isobutene and butadiene, may be and usually arepresent in substantial proportions. I find that the results obtainable by the process hereinabove defined are improved by the preliminary removal of the isobutene and of the butadiene without polymerization. The removal of either of these constituents by polymerization simultaneously results, as I have found, in the loss of substantial quantities of the normal butene, and for this reason should be avoided. The preliminary removal of the butadiene may be accomplished in various ways. I may, for example, admix the fraction containing the olefines of 4 carbon atoms to the molecule with benzo-quinone and hold the materials at a temperature of approximatel 125 C. for a number of hours by which the utadiene will be principally converted to tetra-hydronaphthoquinone from which the unconverted olefines may be separated by fractional distillation.

Another feasible method consists in adding maleic anhydride to such a fraction and to hold the materials in contact at about 100 C. for a number of hours, four hours has been found to yield favorable results. This causes the maleic anhydride to react with the butadiene with the formation of tetra-hydrophthalic anhydride.- On cooling the latter compound becomes almost completely insoluble in the mono olefines and may be separated by decantation and/or filtration.

In my preferred method, however, I separate the butadiene by admixing the said fraction with a slurry of solid-finely divided cuprous chloride in water or an aqueous solu tion. Such a solution may, for example, contain water and HCl in the ratio of 10 b0 parts thereof for every 100 parts of water present. I find, however, that a greater separation efiiciency is achieved by employing a slurry of solid finely divided cuprous. chloride in an aqueous solution containing a chloride of the type of ammonium chloride, viz,

- 0. compound of HCl with ammonia or a subwhich the mono olefines may be separated by decantation and/or filtration, although fractional distillation may be employed if desired, takin the mono olefines over-head and leaving the butadiene-cuprous chloride compound in-the unvaporized material.

The isobutene may be separated by treatment with aqueous sulphuric acid of not exceeding 70%, ILSO content, at temperatures not exceeding 0., although for best results I prefer acid of not exceeding 65%,

H SO, content, at temperatures not exceeding 25 C. The amount of acid should be at least theoretically sufficient to convert the isobutene present into the corresponding mono alkyl sulphate.

As a specific example of the practice of my invention, petroleum oil was subjected to vapor phase cracking at a temperature of between 1050 and 1100 F, recycled stock and a gasoline fraction were separated from the cracked materials, and the remanent gas was then rectified with the production of a fraction consisting predominantly of olefines of 4 carbon atoms to the molecule. The following is a representative analysis of such a fraction:

Per cent 5 Butadiene 15-20 Iso-butene 153O Normal butene 45455 then admixed with aqueous sulphuric acid of 65%, H SO, content, at a tem' erature of about 16 0., the amount of su phuric acid being a slight excess over that necessary to combine with the isobutene present.

After mixing the materials together for a period of about two hours the same were permitted to settle, and the lower layer consisting largely of isobutyl sulphate was withdrawn to be worked up for isobutyl alcohol. The remanent hydrocarbons at this stage consisted almost exclusively of normal butenes and this was admixed with aqueous sulphuric acid of 68%, H 80 content, at a temperature of C. The amount of sulphuric acid was theoretically suflicient to convert the butene present to mono butyl sulphate. At the expiration of two hours the mixing was discon-' tinued and the entire reaction mixture was diluted with about four volumes of cold water. Stratification ensued with the production of an upper layer of oily material insoluble in the lower aqueous layer. The layer of oily material was distilled with a small quantity of water and yielded a substantial pro portion of secondary butyl alcohol. The butyl alcohol resulting from both rectifications was then blended and rectified to separate a constant boiling mixture of secondary butyl alcohol and water therefrom.

The following description is for purposes of illustration and not of limitation, and it is therefore my intention that the invention be limited by the appended claims or their equivalents in which I have endeavored to claim broadly all inherent novelty.

I claim:

1. Process of sulphating normal butene, which comprises admixing the same in liquid phase with aqueous sulphuric acid of from to 70%, H SO content, at temperatures between 30 and'55 C.

2. Process of sulphating normal butene. which comprises admixing same in liquid phase with aqueous sulphuric acid of from to 68%, H SO. content, at temperatures between 35 and 45 C.

BENJAMIN T. BROOKS. 

